--- bison/data/yacc.c	2005-04-25 05:14:22.000000000 +0200
+++ bison-mhx/data/yacc.c	2005-04-30 12:26:31.000000000 +0200
@@ -1316,6 +1316,18 @@
 `----------------------------------------------*/
 yyoverflowlab:
   yyerror (]b4_yyerror_args[_("parser stack overflow"));
+  yydestruct (_("Error: discarding lookahead"),
+	      yytoken, &yylval]b4_location_if([, &yylloc])[);
+  for (;;)
+    {
+]b4_location_if([[      yyerror_range[0] = *yylsp;]])[
+      YYPOPSTACK;
+      if (yyssp == yyss)
+        break;
+      yydestruct (_("Error: popping"),
+      yystos[*yyssp], yyvsp]b4_location_if([, yylsp])[);
+    }
+  yychar = YYEMPTY;
   yyresult = 2;
   /* Fall through.  */
 #endif
--- bison/tests/actions.at	2004-12-20 14:56:38.000000000 +0100
+++ bison-mhx/tests/actions.at	2005-04-30 19:55:20.000000000 +0200
@@ -174,6 +174,9 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
+
+#define YYINITDEPTH 10
+#define YYMAXDEPTH 10
 ]AT_LALR1_CC_IF(
   [#define RANGE(Location) (Location).begin.line, (Location).end.line],
   [#define RANGE(Location) (Location).first_line, (Location).last_line])
@@ -442,6 +445,58 @@
 Parsing FAILED.
 ]])
 
+# Check destruction upon stack overflow
+# -------------------------------------
+# Upon stack overflow, all symbols on the stack should be destroyed.
+# Only check for yacc.c.
+AT_YACC_IF([
+AT_PARSER_CHECK([./input '(x)(x)(x)(x)(x)(x)(x)'], 1,
+[[sending: '(' (address@hidden)
+sending: 'x' (address@hidden)
+thing (address@hidden): 'x' (address@hidden)
+sending: ')' (address@hidden)
+line (address@hidden): '(' (address@hidden) thing (address@hidden) ')' (address@hidden)
+sending: '(' (address@hidden)
+sending: 'x' (address@hidden)
+thing (address@hidden): 'x' (address@hidden)
+sending: ')' (address@hidden)
+line (address@hidden): '(' (address@hidden) thing (address@hidden) ')' (address@hidden)
+sending: '(' (address@hidden)
+sending: 'x' (address@hidden)
+thing (address@hidden): 'x' (address@hidden)
+sending: ')' (address@hidden)
+line (address@hidden): '(' (address@hidden) thing (address@hidden) ')' (address@hidden)
+sending: '(' (address@hidden)
+sending: 'x' (address@hidden)
+thing (address@hidden): 'x' (address@hidden)
+sending: ')' (address@hidden)
+line (address@hidden): '(' (address@hidden) thing (address@hidden) ')' (address@hidden)
+sending: '(' (address@hidden)
+sending: 'x' (address@hidden)
+thing (address@hidden): 'x' (address@hidden)
+sending: ')' (address@hidden)
+line (address@hidden): '(' (address@hidden) thing (address@hidden) ')' (address@hidden)
+sending: '(' (address@hidden)
+sending: 'x' (address@hidden)
+thing (address@hidden): 'x' (address@hidden)
+sending: ')' (address@hidden)
+line (address@hidden): '(' (address@hidden) thing (address@hidden) ')' (address@hidden)
+sending: '(' (address@hidden)
+sending: 'x' (address@hidden)
+thing (address@hidden): 'x' (address@hidden)
+sending: ')' (address@hidden)
+200-209: parser stack overflow
+Freeing nterm thing (address@hidden)
+Freeing nterm line (address@hidden)
+Freeing nterm line (address@hidden)
+Freeing nterm line (address@hidden)
+Freeing nterm line (address@hidden)
+Freeing nterm line (address@hidden)
+Freeing nterm line (address@hidden)
+Parsing FAILED.
+]])
+])
+
 ])